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2016 Round 11 : Overs/Unders Update I

Well there's no point waiting any longer, it seems, there just isn't going to be an Overs/Unders market posted for the Swans v Suns game anytime soon.

Framing markets for this contest seems to have been troubling the TAB all week, with the head-to-head market opening with the Suns at $13 and currently trading with them at $9, and the line market market opening Suns +46.5 @ $1.90 and now showing Suns +42.5 @ $1.70 (which is roughly Suns +37.5 @ $1.90).

So, while we wait for the Suns' market to rise, let's have a look at what's been locked in for the eight other games.

In short, MoSSBODS has spotted a lot of value in the Overs/Unders markets, all of it on the Unders, including one where the total is just 165.5 points.

The bias this week, and in previous weeks, towards Unders wagering is not at all unexpected and was something noted in the pre-season write-up of the Funds. There I foreshadowed a 5:1 Overs:Unders wagering ratio, which is fairly close to the 48:9 ratio we've seen from the Fund so far.

Direct comparison of MoSSBODS' predictions with those of the TAB yields the now-familiar picture of a MoSSBODS forecasting generally lowering scoring.

MoSSBODS' Home team score forecasts this week are between 3 and 17 points lower than the TAB's, the largest differences for Carlton (MoSSBODS 92, TAB 108.5) and the Western Bulldogs (MoSSBODS 81, TAB 95.5). Its away team score forecasts are also generally lower than the TAB's, though it does have the Saints scoring one extra point (MoSSBODS 78, TAB 77). The most extreme difference on away teams relates to the Eagles, who MoSSBODS predicts will score only 65 points but who the TAB has scoring 93 points.

So far this season, MoSSBODS' and the TAB's records on team score prediction has been as follows:

  • Home Team Scores: MAE - MoSSBODS 21.4 / TAB 18.9; Ave Error - MoSSBODS -10 / TAB -5
  • Away Team Scores: MAE - MoSSBODS 19.4 / TAB 20.2; Ave Error - MoSSBODS -2 / TAB +4

Those average error statistics reveal that MoSSBODS has tended to underestimate scores for home and for away teams, and the MAEs reveal that MoSSBODS has, on average, been nearer away team scores than home team scores.

MoSSBODS' aggregate score forecasts are lower than the TAB's for the eight games that've been posted, by amounts ranging from 3 to 43 points, the latter difference relating to the Dogs v Eagles game where MoSSBODS is predicting a 146 point aggregate and the TAB 188.5. That's comfortably the biggest difference so far this season.

(On the positive side, the market has responded as if it believes these aggregates are too high as well: in seven of the eight markets the price for the Unders has shortened or the aggregate has been reduced during the period since the markets opened with those aggregates shown above.)

Despite their stark differences, both MoSSBODS and the TAB expect the Hawthorn v Melbourne game to be the high-scoring game of the round and the Fremantle v Essendon game to be one of the two lowest-scoring.

The TAB and MoSSBODS records on aggregate prediction this year so far have been:

  • MAE: MoSSBODS 29.2 / TAB 27.0
  • Ave Error: MoSSBODS -12 / TAB -1

MoSSBODS has, therefore, tended to underestimate aggregates by about 2 goals per game and has been about 2 points per game further away from the aggregate than the TAB.

Lastly, let's review the TAB's and MoSSBODS' records on margin prediction (from the home team's perspective when calculating errors):

  • MAE: MoSSBODS 29.4 / TAB 29.3
  • Ave Error: MoSSBODS -8 / TAB -9

Consistent with our earlier analysis showing that home teams have scored more points, on average, than MoSSBODS has predicted, home teams have also won by 8 points more (or lost by 8 points less), on average, than MoSSBODS has expected.

Also, for the first time this season, MoSSBODS' MAE exceeds the TAB's, if only by one-tenth of a point per game.